A046366 Composite numbers divisible by the palindromic sum of their palindromic prime factors (counted with multiplicity).
4, 16, 27, 308, 440, 528, 594, 5445, 5808, 6534, 8085, 9702, 11550, 13860, 14784, 16500, 16632, 18711, 19800, 21120, 22275, 23760, 25344, 26730, 28512, 32076, 37268, 53240, 63888, 94864, 135520, 152460, 162624, 181500, 182952, 193600
Offset: 1
Examples
1041714 = 2 * 3^3 * 101 * 191 -> Sum of factors is 303 -> 1041714 / 303 = 3438 exactly.
Links
- Giovanni Resta, Table of n, a(n) for n = 1..1387 (terms < 10^10)
Crossrefs
Cf. A046367.
Programs
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Maple
isA046366 := proc(n) local sofpp ; if isA046355(n) then sofpp := A262049(n) ; if modp(n,sofpp) = 0 then true; else false; end if; else false; end if; end proc: for n from 2 to 1000 do if isA046366(n) then printf("%d,",n) ; end if; end do: # R. J. Mathar, Sep 09 2015
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Mathematica
palQ[n_]:=Reverse[x=IntegerDigits[n]]==x; Select[Range[4,10^5],!PrimeQ[#]&&And@@palQ/@Join[{y=Total[Times@@@(x=FactorInteger[#])]},First/@x]&&IntegerQ[#/y]&](* Jayanta Basu, Jun 05 2013 *)
Comments